Jr. Isasi et al., A STUDY OF THE DILATION OF THE UNIT-CELL OF METALLOCENE ISOTACTIC POLY(PROPYLENES) - THE MONOCLINIC FORM, Journal of polymer science. Part B, Polymer physics, 35(15), 1997, pp. 2511-2521
The lattice parameters of a series of monoclinic metallocene poly(prop
ylenes) of constant molecular weight are measured as a function of def
ect content, that vary between 0.3 and 2.35 total defects per 100 mono
meric units. The parameters are also measured as a function of molecul
ar weight for a fixed defect content and as a function of the crystall
ization temperature. The b axis is found to increase with decreasing i
sothermal crystallization temperature whereas only small changes are f
ound for samples rapidly crystallized. The a and c axis showed basical
ly no variation with crystallization temperature. The parameters of th
e unit cell were essentially constant with varying defect content in t
he poly(propylene) chain. Lack of observed effect on the dilation of t
he unit cell by increasing defects is a consequence of the rapid cryst
allization required to ensure formation of monoclinic crystals. The un
it cell parameters increased as a mild function of the molecular weigh
t. (C) 1997 John Wiley & Sons, Inc.